The Air Force’s push to adopt renewable energy and find ways to conserve its electricity consumption has made a considerable dent in its facilities power bill, but the service still has the potential for further savings if it can figure out how to leverage its massive real estate portfolio.

“I would say that at the Air Force, we’re still at the very beginning stages, at least in energy technologies, in leveraging our size and scale,” Miranda Ballentine, assistant secretary for installations, environment and energy, told the Los Angeles Times.

“We still function as essentially independent little towns all across the country, and we have not yet really cracked the code on how to leverage that scale to drive down prices of these technologies for ourselves,” she said.

In contrast, Ballentine’s previous employer, Wal-Mart, has been very successful in leveraging its size and scale to reduce the cost of implementing energy technologies, she said.

Of course, working for the federal government requires following a multitude of procurement rules and related policies that don’t exist in the corporate world.

“The federal acquisition rules absolutely make procurement of technologies more complicated and more difficult,” Ballentine said.

Changes made since 2010 helped the Air Force save $1.9 billion on its total energy bill in 2015, which came to $8.5 billion. About 86 percent of its energy cost goes toward the purchase of jet fuel.